This invention relates in general to apparatus for finishing a plurality of receiver sheets from a reproduction machine into a completed booklet, and more particularly to a finishing apparatus capable of binding a plurality of stacked receiver sheets together at any selected location along an edge of the receiver sheet stack.
In an effort to increase the overall throughput rate of reproduction machines to reproduce finished complete sets, certain such machines have been provided with finisher apparatus which can assemble individual receiver sheets into completed booklets. One type of finisher apparatus employs a stapler device for automatically binding a plurality of receiver sheets into a desired completed booklet. The stapler device may be of the type utilizing preformed staples of a particular size, such as shown in U.S. Pat. No. 4,313,670, issued Feb. 2, 1982, in the name of Caldwell for example. Alternatively, to increase the capability of a stapler device to bind a wide range of different numbers of sheets without producing poorly fastened booklets or undesirable overlapped staples, stapler devices have been proposed which produce staples of different lengths. Such devices utilize either preformed staples of different lengths or a continuous length of staple material from which desired length staples are cut. When preformed staples are used, the entire stapling mechanism has to be changed to accommodate the different length staples. A device using continuous staple material is shown in U.S. Pat. No. 4,318,555, issued March 9, 1982, in the name of Adamski et al. Devices utilizing continuous staple material are more efficient than devices utilizing preformed staples in that different length staples can be selected depending upon the number of sheets to be bound together into a booklet.
In general, staplers of either of the above-described types place staples at a preselected location relative to a sheet stack edge. In order to accommodate a variety of staple locations relative to the sheet stack edge, it has been proposed to provide a multiplicity of adjustably located stapler heads (see for example U.S. Pat. No. 4,516,714, issued May 14, 1985, in the name of Braun et al.). The inclusion of multiple stapler heads results in a significantly complicated and expensive finisher apparatus structure. Moreover, even with adjustable multiple head staplers, the number of staple locations which can be provided along a sheet stack edge is limited by the location of the heads relative to the sheet stack edge.